Optically neutral laser shield

An optical device that is optically neutral to normal light but absorbs highly collimated light is formed as a mosaic of optical cells. Each cell has at least two refracting surfaces and a non linear material at a focus internal to those surfaces. In one form, the cell comprises two pairs of lenses with a layer of non-linear light absorbent material interposed between the lenses of each pair. The lens elements can be one-power telescopes. A first lens element focuses highly collimated light at its entrance aperture on the non-linear layer. The intensity of the focused light causes the non-linear layer to become opaque or reflective and thereby reduce, or substantially block, the transmission of highly collimated light. The second pair of lenses inverts the re-collimated light exiting the first lens pair. By arranging the optical cells in an array, it is possible to obtain a coherence of the light diffracted from individual cells to produce a wave front from the mosaic as a whole having a resolution that is superior to that of the cells.

Patent #: 5208698 Issue Date: May 4, 1993